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Lights Work on Even Speed Steps Only

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Posted by wp8thsub on Tuesday, July 26, 2011 7:52 PM

rrinker

Do you have another loco you can try setting the address ont he program track? Perhaps there is a setting in the Pro Cab that has changed to a default of assigning 14 speed step mode. Now that it's working, try the program track again and just set the address, nothign else. Then read back CV29 and see what you end up with. Should generally be 6 or 38 for short or long address unless you also go through the prompts for CV29 and turn of DC.

OK, here's what I got - the value I'm getting for CV 29 after re-setting the address ONLY is the expected 34 (28/128 speed step mode on, DC mode off, 4-digit address on).  I tried these steps with the "problem" decoder in question, and it still works OK, although I didn't reset it to default first this time.  Interestingly though, that particular decoder gave me a readback of 34 on CV 29 before I re-assigned its address, but gives a "cannot read CV" after.

Rob Spangler

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Posted by rrinker on Tuesday, July 26, 2011 6:51 PM

wp8thsub

 richhotrain:
 

What I meant, though, was that the CV29 value of 2 sets the 28/128 speed steps mode and only allows 2-digit addresses.  Maybe I am also misunderstanding the "address" setting, but wouldn't you want a CV29 value of 22 to permit 4-digit addresses to be programmed?

 

Note that I was trying to isolate symptoms, so picked the value of 2 for that purpose only.   According to the Digitrax knowledge base, a value of 22 also provides for only a 2-digit address http://tsd.digitrax.com//index.php?a=1274 .

Right now the big head scratcher for me is why the decoder responds differently depending on whether the address is assigned on the programming track vs. in ops mode.  A full reset to default should clear out CV 29 anyway, and I know I'm not setting any values in there other than the one time I tested it as noted earler.

 Do you have another loco you can try setting the address ont he program track? Perhaps there is a setting in the Pro Cab that has changed to a default of assigning 14 speed step mode. Now that it's working, try the program track again and just set the address, nothign else. Then read back CV29 and see what you end up with. Should generally be 6 or 38 for short or long address unless you also go through the prompts for CV29 and turn of DC. It's possible that that decoder doesn't like what it considers a short address being programmed as a long address, which is how NCE prefers it (to save the short addresses for CV19 consisting). Digitrax has a hard split, 0-127 is a short address, period, and 128+ is a long address, period. NCE can use 1-127 as short OR long, depending on CV29 and how you select the address on the cab.

 To further confuse matters, for Lenz, 0-99 is a short address, period, and 100+ is a long address, period.

                         --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by rrinker on Tuesday, July 26, 2011 6:46 PM

richhotrain

 rrinker:

 CV29=2 is short address, 28/128SS mode, no DC conversion, no speed tables. For ALL decoders.

CV29=22 would be short address, DC conversion on, 28/128SS mode, 28 step speed table enabled.

Speed table and number of speed steps are 2 different things.

                 --Randy

 

Randy, thanks, I stand corrected. 

What I meant, though, was that the CV29 value of 2 sets the 28/128 speed steps mode and only allows 2-digit addresses.  Maybe I am also misunderstanding the "address" setting, but wouldn't you want a CV29 value of 22 to permit 4-digit addresses to be programmed?

Rich

CV29=22 is still a short address. 32 would be 14 SS, no speed table, no DC,  but long address, 34 is 28/128 SS, long address, no speed table, no DC

                          --Randy

 


Modeling the Reading Railroad in the 1950's

 

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Posted by wp8thsub on Tuesday, July 26, 2011 5:39 PM

richhotrain
 

What I meant, though, was that the CV29 value of 2 sets the 28/128 speed steps mode and only allows 2-digit addresses.  Maybe I am also misunderstanding the "address" setting, but wouldn't you want a CV29 value of 22 to permit 4-digit addresses to be programmed?

Note that I was trying to isolate symptoms, so picked the value of 2 for that purpose only.   According to the Digitrax knowledge base, a value of 22 also provides for only a 2-digit address http://tsd.digitrax.com//index.php?a=1274 .

Right now the big head scratcher for me is why the decoder responds differently depending on whether the address is assigned on the programming track vs. in ops mode.  A full reset to default should clear out CV 29 anyway, and I know I'm not setting any values in there other than the one time I tested it as noted earler.

Rob Spangler

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Posted by richhotrain on Tuesday, July 26, 2011 5:29 PM

rrinker

 CV29=2 is short address, 28/128SS mode, no DC conversion, no speed tables. For ALL decoders.

CV29=22 would be short address, DC conversion on, 28/128SS mode, 28 step speed table enabled.

Speed table and number of speed steps are 2 different things.

                 --Randy

 

Randy, thanks, I stand corrected. 

What I meant, though, was that the CV29 value of 2 sets the 28/128 speed steps mode and only allows 2-digit addresses.  Maybe I am also misunderstanding the "address" setting, but wouldn't you want a CV29 value of 22 to permit 4-digit addresses to be programmed?

Rich

Alton Junction

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Posted by rrinker on Tuesday, July 26, 2011 2:25 PM

 CV29=2 is short address, 28/128SS mode, no DC conversion, no speed tables. For ALL decoders.

CV29=22 would be short address, DC conversion on, 28/128SS mode, 28 step speed table enabled.

Speed table and number of speed steps are 2 different things.

 

                --Randy

 

 


Modeling the Reading Railroad in the 1950's

 

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Posted by richhotrain on Tuesday, July 26, 2011 2:13 PM

I am no expert on Digitrax decoders but if you set the value of CV29 to 2, you enable the 28/128 speed step table but only allow 2-digit addresses.

Wouldn't you need to set the CV29 value to 22 to allow 4-digit addresses while enabling the 28/128 speed step table?

Rich

Alton Junction

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Posted by wp8thsub on Tuesday, July 26, 2011 1:44 PM

rrinker

Did you maybe press 1 instead of Enter on the SPEED prompt? That would set the decode to 14SS instead of 28/128.

Pretty sure I didn't.  And I doubt I could be inadvertently doing that multiple times despite my inherently bumbling nature.

And it does not look like there's even a way to set the PowerCab to send 14 speed steps, at least, it's not listed in the manual. Dunno how else CV29 could have gotten set to 14SS other then some inadvertat gefingerpoken or hitting the wrong dropdown in JMRI if it was programmed through JMRI.                       

I'm using the Pro Cab instead of the Power Cab, but I see no option for 14-step mode with it either.  Maybe there's a decoder gremlin at work.

Rob Spangler

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Posted by rrinker on Tuesday, July 26, 2011 10:18 AM

 The only way it can get a value in CV29 is what the DCC system gives it, the decoder does no calculations on that.

Did you maybe press 1 instead of Enter on the SPEED prompt? That would set the decode to 14SS instead of 28/128. No current systems, when they fix CV29 for short or long address, EVER set it to 14 speed steps. And it does not look like there's even a way to set the PowerCab to send 14 speed steps, at least, it's not listed in the manual. Dunno how else CV29 could have gotten set to 14SS other then some inadvertat gefingerpoken or hitting the wrong dropdown in JMRI if it was programmed through JMRI.

                         --Randy

 


Modeling the Reading Railroad in the 1950's

 

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Posted by wp8thsub on Tuesday, July 26, 2011 9:49 AM

richhotrain

If you reset the decoder back to the factory default value, you enabled the 28/128 speed step table, disabling the 14 speed step table.

Understood.  Note however that I had reset the decoder to default previosuly and got the strange light behavior every time I re-programmed an address on the programming track.  I never plugged a value into CV 29 in that process, which is why I never suspected the 14-step table could have been activated.

Before resetting the decoder to its factory default value, what was the CV29 value that you had set?

Nothing was set by me, but the readback I got was telling me the value in CV 29 was 0, suggesting the 14-step table was active assuming the readback was correct.  On the advice above I set it to 2 using the table at http://www.2mm.org.uk/articles/cv29%20calculator.htm, but that didn't change the light behavior, so that's when I reset to default again and programmed the address in ops mode.

So here's how it stands - assign address (or apparently anything else) on programming track = lights don't work on odd steps in 28 step mode or on 128 step mode at all; assign address on the main = lights work perfectly.  Decoder left on default address of 3 = lights work perfectly every time.

I'm suspecting something could be funky with the decoder inserting an incorrect value into CV 29 when it's on the programming track, but still have no clue how that could happen, or why ops mode programming would prevent it. 

Rob Spangler

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Posted by richhotrain on Tuesday, July 26, 2011 5:54 AM

If you reset the decoder back to the factory default value, you enabled the 28/128 speed step table, disabling the 14 speed step table.

Before resetting the decoder to its factory default value, what was the CV29 value that you had set?

Rich

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Posted by wp8thsub on Monday, July 25, 2011 9:12 PM

I've achieved success with the lights, but I'm not sure why yet.

I set CV 29 to disable 14 speed step mode, but nothing changed.  Hmmmm...

I had previously been messing around with the loco on my programming track, but recalled that the lights worked fine when my buddy and I first dropped the decoder in at his house, and the loco address was programmed there on the main.  I reset the decoder back to default again, and this time programmed the address on the main in ops mode - bingo!  The lights work perfectly.  I don't know why this "fix" worked, but it did.

Rob Spangler

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Posted by wp8thsub on Monday, July 25, 2011 5:02 PM

Thanks to all for the responses.  I will try the 14-step to 28-step fix next time I head for the train room and report back.

Rob Spangler

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Posted by richhotrain on Monday, July 25, 2011 4:06 PM

It is definitely set for 14 speed steps, and that is the problem.  It has happened before to me.  It can be reset to 28 speed steps by changing the value for CV29.

Rich

Alton Junction

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Posted by rrinker on Monday, July 25, 2011 3:56 PM

 After a reset it shouldn;t be on 14 speed steps anymore - unless you are doing the PowerCab's reset - don;t do that on non-NCE decoders, it sets specific CVs that don;t apply to all decoders. For a Digitrax decoder, set CV8=8 for a rest. Don't worry about reading it back, it won;t read back an 8, in fact for a Digitrax decoder reading CV8 should return 129, which is their manufacturer ID.

 But do check CV29, it should be either 6, for a true 2-digit address (no leading 0's on the PowerCab) or 38 for a long address (128+, or a smaller number WITH leading 0's, like 005). Other values, if you turn on speed tables, or disable DC operation, or need to change the default direction.

            --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by Hamltnblue on Monday, July 25, 2011 3:44 PM

Here's a link to a CV29 calculator

http://www.2mm.org.uk/articles/cv29%20calculator.htm

Just click what you want and it gives the value to enter as CV29

The most common value to use is 34.

Springfield PA

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Posted by Hamltnblue on Monday, July 25, 2011 3:30 PM

Yes

If the decoder is set to 14 speed step mode and the controller is set to 28 you can have light issues.

 

Springfield PA

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Posted by jrbernier on Monday, July 25, 2011 3:11 PM

Check to see if you have something set to 14 speed step mode - I have seen this before....

Jim

Modeling BNSF  and Milwaukee Road in SW Wisconsin

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Lights Work on Even Speed Steps Only
Posted by wp8thsub on Monday, July 25, 2011 1:58 PM

I installed a Digitrax DH 165-IP decoder in a new Atlas GP40-2, and everything works great except the lights.  With the decoder at the default address, the lights work fine, but once I program the loco address, the lights (both on the front and rear of the unit) only work in 28 speed step mode, and then only on even speed steps 2 and above.  I've been running it with my NCE Pro Cab, and watching the readout carefully.  I've reset the decoder to default a couple times, and noticed the same thing happening - lights are OK on address 3 but not once an address is programmed.

Has anybody else experienced this and/or knows what's up? 

Apologies if this has been asked in the forum before, but I didn't find it.

 

Rob Spangler

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